MIL-DTL-12211G
6.5 Tin whisker growth. The use of alloys with tin content greater than 97 percent, by mass, may
exhibit tin whisker growth problems after manufacture. Tin whiskers may occur anytime from a day to
years after manufacture and can develop under typical operating conditions, on products that use such
materials. Conformal coatings applied over top of a whisker-prone surface will not prevent the formation
of tin whiskers. Alloys of 3 percent lead, by mass, have shown to inhibit the growth of tin whiskers. For
additional information on this matter, refer to ASTM-B545 (Standard Specification for Electrodeposited
Coatings of Tin).
6.6 Definitions.
6.6.1 Cycling. Cycling, as used herein, will mean opening and subsequent closing of contacts. Switch
cycling frequency shall be the maximum that will allow the electrical contacts to open and close, with the
contacts open during half of each cycle.
6.7 Environmentally preferable material. Environmentally preferable materials should be used to the
maximum extent possible to meet the requirements of this specification. As of the dating of this
document, the U.S. Environmentally Protection Agency (EPA) is focusing efforts on reducing 31 priority
chemicals. The list of chemicals is available on their website at
https://www.epa.gov/epaoswer/hazwaste/minimize/chemlist.htm. Further information is available at the
following EPA site: https://www.epa.gov/epaoswer/hazwaste/minimize/. Included in the EPA list of 31
priority chemicals are cadmium, lead, and mercury. Use of the materials on the list should be minimized
or eliminated unless needed to meet the requirements specified herein (see Section 3).
6.8 Subject term (key work) listing.
Instrumentation, automotive, safety
Lamps, warning instruments
Warning device, waterproof
6.9 Changes from previous issue. The margins of this specification are marked with vertical lines to
indicate where changes from the previous issue were made. This was done as a convenience only and
the Government assumes no liability whatsoever for any inaccuracies in these notations. Bidders and
contractors are cautioned to evaluate the requirements of this document based on the entire content
irrespective of the marginal notations and relationship to the last previous issue.
Custodians:
Preparing activity:
Army - AT
DLA - CC
Navy - EC
Air Force - 85
(Project 5930-2008-043)
DLA - CC
NOTE: The activities listed above were interested in this document as of the date of this document.
Since organizations and responsibilities can change, you should verify the currency of the information
above using the ASSIST Online database at https://assist.daps.dla.mil/.
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